Freddie Flintstone

I obtained planning permission to alter the front/side of my property (I could not proceed by permitted development). It involved taking down part of the walls on one side of the property and reducing the roof size. (The changes can be seen from the street outside) The builder started to take down the roof and walls but unexpectedly found steel beams holding the roof running across the room onto the parts of the walls that were to be removed. By this time part of the roof had been removed and temporarily covered to minimise water ingress and the property could not be put back to its original condition easily. Building Regulations came out and were shown the steel beams and plans passed by planning and said that the steel beams could not be removed and the part of the walls the steel beams were sitting on had to remain for structural reasons but this was not as per the plans. The work was completed with walls that were due to removed still in place with the beams still sitting on them and the work has now been completed and passed by Building Regulations. I have been told that in these circumstances Building Regulations decision takes precedence over planning and I should proceed as per the Building Regulations decision (I have removed less of the wall than was originally planned but more than is shown in the plans remains. Nothing extra has been built onto the property). I am also informed that in these circumstances I do not need to revert back to planning. Is this correct or do I have to revert back to planning and if so, is this likely to be a problem as the work has been completed as Building Regulations stated? The council in question is in the South East of England if it is relevant.